SY58021U

4GHz, 1:4 LVPECL Fanout

Buffer/Translator with Internal Termination

Precision Edge

®

Precision Edge is a registered trademark of Micrel, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (

General Description

The SY58021U is a 2.5V/3.3V precision, high-speed, fully

differential 1:4 LVPECL fanout buffer. Optimized to provide

four identical output copies with less than 15ps output

process clock signals as fast as 4GHz.

The differential input includes Micrel’s unique, 3-pin input

termination architecture interfaces to differential LVPECL,

CML, and LVDS signals (AC- or DC-coupled) as small as

100mV without any level-shifting or termination resistor

networks in the signal path. For AC-coupled input interface

applications, an on-board output reference voltage (V

REFAC

)

is provided to bias the VT pin. The outputs are 100k

LVPECL compatible, with extremely fast rise/fall times

guaranteed to 70fs.

The SY58021U operates from a 2.5V ±5% supply or 3.3V

±10% supply and is guaranteed over the full industrial

temperature range (–40°C to +85°C). For applications that

require faster rise/fall times, or greater bandwidth, consider

the SY58022U 1:4 fanout buffer with 400mV LVPECL

output swing, or the SY58020U 1:4 CML fanout buffer. The

SY58021U is part of Micrel’s high-speed, Precision Edge

®

product line.

Data sheets and support documentation can be found on

Precision Edge

®

Features

• Precision 1:4 LVPECL fanout buffer

• Low jitter performance:

• Accepts an input signal as low as 100mV

• Unique input termination and VT pin accepts DC-

coupled and AC-coupled differential inputs: LVPECL,

LVDS, and CML

• 100k LVPECL-compatible 800mV swing output

• Power supply 2.5V ±5% and 3.3V ±10%

• −40°C to +85°C temperature range

• Available in 16-pin (3mm × 3mm) QFN package

Applications

• All SONET and GigE clock distribution

• Fibre Channel clock and data distribution

• Backplane distribution

• High-end, low-skew, multiprocessor, synchronous clock

distribution

Block Diagram

September 2011

M9999-090111-B